New BMW M4 Convertible revealed

BMW reveals the new M4 Convertible

By Tim Kendall | 4th April 2014

The new BMW M4 Convertible – what is it?

Not quite hot on the heels of its tin-top siblings comes this: the new 2014 BMW M4 Convertible. This is the third body style in the M3/M4 line-up to get the full-fat M-Division treatment – and arguably the one that’ll be more revered by boulevard gangsters than M-purists. Like its motorway name-inspired brethren, the M3 saloon and M4 coupé, this drop-top version gets the (whisper it..) turbocharged 3.0 straight-six with a wholesome 431hp.

Out goes the n/a 4.0-litre V8…

M4 Convertible – the details

This is an M-car so it’s all about the engine. And BMW isn’t being shy about the M4’s performance credentials, calling it a ‘powerhouse’, which, with the full twist of 550Nm and 431hp available from 1,850rpm sounds more than reasonable. It should be a different kettle of fish to the previous generation high-revving, slightly peaky 414hp V8, although it’ll rev all the way to a heady 7,300rpm so it’s no wham, bam all over by 4k job.

…in comes a 3.0-litre straight-six twin turbo

Developed by BMW M, the motor’s low-down grunt comes from two mono-scroll turbochargers which should give the M4 a markedly different character to the old car. High-precision direct injection, valvetronic variable valve timing and Double-VANOS variable camshaft control complete the engine geeks wet dream. Power is channeled through a choice of six-speed manual or a seven-speed M double clutch gearbox. The former manages the magic 62mph in 4.6 seconds, the latter in 4.4 seconds.

M4 gets a folding hard-top instead of a fabric roof again

What about the chassis?

Should be finely honed. There’s double-joint spring strut suspension at the front with a five-link aluminium axle at the rear, both of which have an ‘M-specific’ set-up. A variable electro-mechanical rack and pinion steering system is also said to deliver the ‘seemingly impossible combination’ of maximum steering precision, response, assistance and fuel efficiency. You wouldn’t bet against it handling quite tidily then.

And there’s a whole raft of other bits with M prefixes… M Servotronic steering moderates the steering weight according to speed and features three modes from comfort, through to sport and sport+. The BMW M Compound brakes are said to be lightweight with good fade resistance. Wait, there’s more. It wouldn’t be a true M without a trick differential and you’ve guessed it, the M4 Convertible gets an active M Differential said to give better directional stability and traction, particularly when playing the hooligan out of corners. There’s also an electronically controlled multi-plate limited slip differential linked to the DSC (Dynamic Stability Control) system. No M for that one mind.

Anything else of note about the M4 cab?

There’s plenty more to tell you, but the salient bits are thus:

Weight saving measures including extensive use of aluminium for the body and chassis, helping it shed 60kg over the old M3 cab. Kerb weight: 1,750kg.

Aerodynamic measures include M side gills with integral air breathers behind the front wheels: said to be instrumental in reducing drag, ditto the ‘twin stalk’ door mirrors;